Precipitation-hardened stainless steel alloys

Abstract

To provide precipitation-hardened stainless steel alloys.SOLUTION: A precipitation-hardened stainless steel alloy is disclosed including, by weight: 14.0-16.0% Cr; 6.0-7.0% Ni; 1.25-1.75% Cu; 0.5-1.0% Mo; 0.40-0.85% Nb; 0.025-0.05% C; up to 1.0% Mn; up to 1.0% Si; up to 0.1% V; up to 0.1% Co; up to 0.1% Sn; up to 0.02% N; up to 0.025% P; up to 0.05% Al; up to 0.008% S; up to 0.005% Ag; up to 0.005% Pb; up to 0.1% As; up to 0.01% Sb; and the balance Fe. The alloy has a ratio of Nb:(C+N) of at least 15:1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to precipitation hardening type stainless steel alloys. More particularly, the present disclosure relates to precipitation hardening That's all. stainless steel alloys having a niobium :( carbon + nitrogen ) total ratio of type precipitation hardening stainless steel alloys.

Background Art

[0002] The rotation of gas turbines parts , particularly moving blade (bucket) and stator wings (nozzle) including compressor airfoils and other driving metallic alloys used in applications exposed to severe parts conditions must have high strength, toughness, fatigue resistance driving and other physical and mechanical properties and to provide these essential combination properties of the machines. In addition, the alloys used must also have sufficient resistance to chloride, sulfate, nitride and and other corrosive species beginning such as exposure to various ionic reaction species in the of extreme driving environment Caused by of the turbine. Corrosion can also cause the driving of the turbine Including to periodic thermal stresses and operation and the generation of surface cracks that propagate under stress High resulting in a decrease in 、 other physical and mechanical properties such as the fatigue strength of the turbine fear There is.

[0003] These and other requirements of( especially Hiro in the range of use but possible This will be at cost ) In order to satisfy , various high-strength stainless steel alloys have been proposed. For example, U.S. Patent No. 3,574,601 to It is now commercially known as the Carpenter Custom 450. Books Qualitatively martensite precipitation hardening type Composition of stainless steel alloy and Other characteristics but Disclosure So The corrosion resistance of this alloy and Focus on mechanical properties but Guess Rare Custom 450 alloy is made of chromium, nickel, and molybdenum. and copper, and carbon and It contains other potential alloying components such as niobium (columbium) and less than 10% retained austenite. and Essentially martensitic with a small amount of delta ferrite (1-2% or less) Microorganism Niobium is produced when carbon is 0.03 by weight. % If present in amounts exceeding this, add at a weight ratio of up to 10 times the amount of carbon. death obtain.

[0004] Other For example, U.S. Patent No. 6743305 to This includes chemical properties and tempering temperature. and Regarding particle size, there is a specific range. And As a result, the rotary steam turbine exhibits both high strength and toughness. parts Modified for use in Good Stainless steel alloy but description So It is. U.S. Patent No. 7985306 to This refers to a rotary gas turbine that has more than 20 times but less than 25 times the amount of niobium as carbon. parts Modified to be particularly suitable for use in compressor blade sections. Good Stainless steel alloy but description So It is. U.S. Patent No. 8663403 to This is a rotary gas turbine that has more than 20 times the amount of niobium as carbon. parts Modified to be particularly suitable for use in compressor blade sections. Good Stainless steel alloy but description So It is.

[0005] The precipitation hardening described above type Martensitic stainless steels have corrosion resistance, mechanical strength parts suitable for use in a rotating steam turbine and and fracture toughness properties, but these alloys are susceptible to intergranular corrosion or and may have an alloy composition with undesirable amounts of individual elements that can adversely affect other properties of the alloy.

Summary of the Invention

[0006] In an exemplary embodiment, the precipitation hardening type stainless steel alloy, by weight standard contains 14.0 - 16.0% Cr, 6.0 - 7.0% Ni, 1.25 - 1.75% Cu, 0.5 - 1.0% Mo, 0.40 - 0.85% Nb, 0.025 - 0.05% C, 1 .0% below of Mn, 1 .0% below of Si, 0 .1% below of V, 0 .1% below of Co, 0 .1% below of Sn, 0 .02% below of N, 0 .025% below of P, 0 .05% below of Al, 0 .008% below of S, 0 .005%<000W116>of Ag, 0 .005% below of Pb, 0 .1% below of As, 0 .01% below of Sb,<000W123>and the balance of Fe. The alloy has a Nb:(C + N That's all. ratio of 15:1 )ratio .

[0007] Aspects of the subject matter of the present disclosure Other are as follows of and the following Implementation section to show .

[0008] precipitation hardening type Stainless steel alloy, weight standard So, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.05% C, 1 0% below Mn, 1 0% below Si, 0 0.1% below V of 0 0.1% below Co, 0 0.1% below Sn, 0 0.02% below N of 0 0.025% below P, 0 0.05% below Al of 0 0.008% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.1% below As, 0 0.01% below Sb, and The alloy contains the remainder Fe, and the ratio is 15:1 That's all. Nb:(C+N )ratio Having, precipitation hardening type Stainless steel alloy.

[0009] weight standard And it contains 0.03-0.05% C, The above-mentioned embodiment Precipitation hardening as described above type Stainless steel alloy.

[0010] weight standard in, 0 0.01% below Including N, The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0011] weight standard So, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.05% C, 1 0% below Mn, 1 0% below Si, 0 0.1% below V of 0 0.1% below Co, 0 0.1% below Sn, 0 0.02% below N of 0 0.025% below P, 0 0.05% below Al of 0 0.008% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.1% below As, 0 0.01% below Sb, 0 0.5% below of other element Consists of Inevitable impurities, and The remainder is Fe, and the alloy is 15:1 That's all. Nb:(C+N) ratio Having, The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0012] weight standard So, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.05% C, 1 0% below Mn, 1 0% below Si, 0 0.1% below V of0 0.1% below Co, 0 0.1% below Sn, 0 0.02% below N of 0 0.025% below P, 0 0.05% below Al of 0 0.008% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.1% below As, 0 0.01% below Sb, and The remainder is Fe, and the alloy is 15:1 That's all. Nb:(C+N) ratio Having, The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0013] weight standard So, 0.025-0.045% C, 0.2-0.5% Mn, 0.2-0.5% Si, 0 0.05% below V of 0 0.01% below Sn, 0 0.01% below N of 0 0.01% below P, 0 0.005% below S of 0 0.01% below As, and 0 0.002% below Including Sb, The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0014] weight standardSo, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.045% C, 0.2-0.5% Mn, 0.2-0.5% Si, 0 0.05% below V of 0 0.1% below Co, 0 0.01% below Sn, 0 0.01% below N of 0 0.01% below P, 0 0.05% below Al of 0 0.005% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.01% below As, 0 0.002% below Sb, 0 0.5% below of other element Consists of Inevitable impurities, and The remainder is Fe, and the alloy is 15:1 That's all. Nb:(C+N) ratio Having, The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0015] weight standard So, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.045% C, 0.2-0.5% Mn, 0.2-0.5% Si, 0 0.05% below V of 0 0.1% below Co, 0 0.01% below Sn, 0 0.01% below N of 0 0.01% belowP, 0 0.05% below Al of 0 0.005% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.01% below As, 0 0.002% below Sb, and The remainder is Fe, and the alloy is 15:1 That's all. Nb:(C+N) ratio Having, The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0016] The alloy contains more than 0.045% C, more than 0.5% Mn, more than 0.5% Si, more than 0.05% V, more than 0.01% Sn, more than 0.01% N, more than 0.01% P, more than 0.005% S, more than 0.01% As, and more than 0.002% Sb. or Those combination has Except for the dot identical contrast If Gold and In comparison, embrittlement is reduced. The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0017] The alloy contains more than 0.045% C, more than 0.5% Mn, more than 0.5% Si, more than 0.05% V, more than 0.01% Sn, more than 0.01% N, more than 0.01% P, more than 0.005% S, more than 0.01% As, and more than 0.002% Sb. or Those combination has Except for the dot identical contrast Compared to alloys, Fracture surface transition The temperature is low. The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0018] The aforementioned alloy is less than 15:1 contrast Nb:(C+N )ratio has Except for the dot identical contrast Compared to alloys, the reverse grain boundaries adjacent to the grain boundaries transformation The susceptibility of austenite to intergranular corrosion is reduced. The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0019] The aforementioned alloy is less than 15:1 contrast Nb:(C+N )ratio has Except for the dot identical contrast Compared to alloys, the opposite is almost true during heat treatment. transformation It does not form austenite. The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0020] The aforementioned alloy has a ratio of less than 15:1 after heat treatment at 577°C for 500 minutes. contrast Nb:(C+N )ratio has Except for the dot identical contrast Rather than alloys, after heat treatment at 577°C for 500 minutes Reverse austenite is 25% or less , The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0021] The alloy is subjected to heat treatment at 577°C for 500 minutes. to , less than 16% transformation Including austenite, The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0022] The alloy is subjected to heat treatment at 577°C for 1000 minutes. to The reverse, less than 25% transformation Including austenite, The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0023] The alloy is subjected to heat treatment at 577°C for 3000 minutes. to The reverse, less than 35% transformation Including austenite, The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0024] All C in the aforementioned alloy and N 9 0% The above Nb-C, Nb-N and It is isolated as the Nb-CN species. The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0025] All C in the aforementioned alloy and N 9 9% The above Nb-C, Nb-N and It is isolated as the Nb-CN species. The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0026] Nb:(C+N) ratio The ratio is 15:1 to 34:1. The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0027] Nb:(C+N) ratio The ratio is 15:1 to 28:1. The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0028] Nb:(C+N) ratio The ratio is 15:1 to 18:1. The above-mentioned embodiment any of crab Described precipitation hardening type Stainless steel alloy.

[0029] These of the subject and Other features, characteristics, andThe advantages will be better understood by referring to the attached diagrams and reading the detailed explanation below. [Brief explanation of the drawing]

[0030] [Figure 1] The only figure is a JMaPro software simulation comparing the formation of reverse transformation austenite over time at 577°C in GTD450 stainless steel alloys with 0.001% and 0.03% N content. [Modes for carrying out the invention]

[0031] Exemplary precipitation hardening type A stainless steel alloy is provided. Embodiments of this disclosure are one of those disclosed herein. or Precipitation hardening without utilizing multiple characteristics type Compared to stainless steel alloys, decreased Susceptibility to intergranular corrosion , decreased reverse transformation Formation of austenite , decreased Embrittlement Low fracture transition temperature increased carbon and Nitrogen sequestration , or Those combination It holds.

[0032] In one embodiment, precipitation hardening occurs. type Stainless steel alloy is heavy standard So, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.05% C, 1 0% below Mn, 1 0% below Si, 0 0.1% below V of 0 0.1% below Co, 0 0.1% below Sn, 0 0.02% below N of 0 0.025% below P,0 0.05% below Al of 0 0.008% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.1% below As, 0 0.01% below Sb, and The alloy contains the remaining Fe, and is 15:1 That's all. Nb:(C+N )ratio It holds.

[0033] Another In this embodiment, precipitation hardening type Stainless steel alloy is heavy standard So, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.05% C, 1 0% below Mn, 1 0% below Si, 0 0.1% below V of 0 0.1% below Co, 0 0.1% below Sn, 0 0.02% below N of 0 0.025% below P, 0 0.05% below Al of 0 0.008% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.1% below As, 0 0.01% below Sb, 0 0.5% below of other element Consists of Inevitable impurities, or 0 0.4% below of other element Consists of Inevitable impurities, or 0 0.3% below of other element Consists of Inevitable impurities, or 0 0.2% below of other element Consists of Inevitable impurities, or 0 0.1% below of other element Consists of Inevitable impurities, or 0 0.05% below of other element Consists of Inevitable impurities, or 0 0.01% below of other element Consists of Inevitable impurities, and The remainder is Fe, and the alloy is 15:1 That's all. Nb:(C+N )ratio It holds. other element Consists of Inevitable impurities as Limited It is not something that should be done. However, titanium One example is... .

[0034] And yet another In this embodiment, precipitation hardening type Stainless steel alloy is heavy standard So, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.05% C, 1 0% below Mn, 1 0% below Si, 0 0.1% below V of 0 0.1% below Co, 0 0.1% below Sn, 0 0.02% below N of 0 0.025% below P, 0 0.05% below Al of 0 0.008% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.1% below As, 0 0.01% below Sb, and The remainder is Fe, and the alloy is 15:1 That's all. Nb:(C+N )ratio It holds.

[0035] Nb:(C+N) in any of the embodiments described above )ratio 15:1 That's all. For example, limited It is not something that should be done. However, 15:1~34:1 , or 15:1~32:1 , or 15:1~30:1 , or 15:1~28:1 , or 15:1~26:1 , or 15:1~24:1 , or 15:1~22:1 , or 15:1~20:1 , or 15:1~18:1 , or 15:1~17:1 , or 15:1~16:1 , or 16:1~18:1 , or 17:1~19:1 , or 18:1~20:1 , or Those The section Minute range Or in combination It's okay to have it.

[0036] Austenite is precipitation-hardened according to the disclosure. type Retained austenite in stainless steel alloys and reverse transformation Austenite can exist in two forms. Retained austenite undergoes precipitation hardening. type This is austenite that withstands the formation of stainless steel alloys and does not convert to martensite during the formation process. Retained austenite undergoes precipitation hardening. type With proper care taken during the heat treatment in the formation of stainless steel alloys, or After formation, the material is precipitation-hardened by cryogenic heat treatment. type Reduced from stainless steel alloy or exclusion deathObtainable. Residual austenite is undesirable, however. 、 This can be dealt with using conventional methods. However, the opposite is true. transformation Austenite is Analysis hardening type Stainless steel alloy During heat treatment or After initial formation Other heat exposure dew time It is formed from martensite, and after formation to cooling Even if This is austenite that does not revert to martensite. (Cryogenic treatment) and other Publicly known This method involves completely remelting the alloy. If ,reverse transformation Austenite content Successfully and lightly decrease It is not possible . theory to It is not something that restricts you, but rather the opposite. transformation Austenite is carbon in alloys and It is stabilized by the presence of nitrogen, and thereby reverse transformation This is thought to prevent austenite from being converted to martensite, especially in the reverse grain boundaries adjacent to them. transformation Austenite formation is a form of precipitation hardening against intergranular corrosion. type Increasing the sensitivity of stainless steel alloys fear There is.

[0037] precipitation hardening type Stainless steel alloys have a ratio of less than 15:1 contrast Nb:(C+N )ratio has Except for the dot identical contrast Compared to alloys, the reverse grain boundaries adjacent to the grain boundaries transformation Reduced susceptibility of austenite to intergranular corrosion. death Obtain. Precipitation hardening. type Stainless steel alloys have a ratio of less than 15:1 contrast Nb:(C+N )ratio has Except for the dot identical contrast Compared to alloys, the opposite is almost true during heat treatment. transformation It may not form austenite. Precipitation hardening type C in stainless steel alloy and N 9 0% That's all. , or 9 5% That's all. , or 9 8% That's all. , or 9 9% That's all. , or 9 9.5% That's all. , or 9 9.9% That's all. , Or all Nb-C, Nb-N and It may be isolated as an Nb-CN species.

[0038] Referring to the figure, in one embodiment, precipitation hardening occurs. type Stainless steel alloys have a ratio of less than 15:1 after heat treatment at 577°C for 500 minutes. contrast Nb:(C+N )ratio has Except for the dot identical contrast Rather than alloys, after heat treatment at 577°C for 500 minutes Reverse austenite is 25% or less . precipitation hardening type After heat treatment at 577°C for 500 minutes, the stainless steel alloy to , less than 16% transformation Containing austenite, after heat treatment at 577°C for 1000 minutes to The reverse, less than 25% transformation Containing austenite, after heat treatment at 577°C for 3000 minutes to The reverse, less than 35% transformation Contains austenite.

[0039] Precipitation hardening of any of the embodiments described above type Stainless steel alloy is heavy standard in, 0 0.018% below N of or 0 0.016% below N of or 0 0.015% below N of or 0 0.014% below N of or 0 0.012% below N of or 0 0.010% below N of or 0 0.010% below N of or 0 0.008% belowN of or 0 0.005% below N of Or Those The section Minute range or combination It may have.

[0040] Precipitation hardening of any of the embodiments described above type Stainless steel alloy is heavy standard So, 0.03-0.05% C, or 0.025-0.045% C, or 0.03-0.045% C, or 0.035-0.05% C, or 0.035~0.045% C, or 0.04-0.05% C, or 0.04-0.045% C, or 0.045-0.05% C, Or Those The section Minute range or combination It may have.

[0041] Precipitation hardening of any of the embodiments described above type Stainless steel alloy is heavy standard in, 0 0.9% below Mn, or 0 0.8% below Mn, or 0 0.7% below Mn, or 0 0.6% below Mn, or 0 0.5% below Mn, or 0 0.4% below Mn, or 0 0.3% below Mn, or 0.2-0.5% Mn, or 0.2-0.3% Mn, or 0.3-0.4% Mn, or 0.4-0.5% Mn, Or Those The section Minute range or combination It may have.

[0042] Precipitation hardening of any of the embodiments described above typeStainless steel alloy is heavy standard in, 0 0.9% below Si, or 0 0.8% below Si, or 0 0.7% below Si, or 0 0.6% below Si, or 0 0.5% below Si, or 0 0.4% below Si, or 0 0.3% below Si, or 0.2-0.5% Si, or 0.2-0.3% Si, or 0.3-0.4% Si, or 0.4-0.5% Si, Or Those The section Minute range or combination It may have.

[0043] Precipitation hardening of any of the embodiments described above type Stainless steel alloy is heavy standard in, 0 0.09% below V of or 0 0.08% below V of or 0 0.07% below V of or 0 0.06% below V of or 0 0.05% below V of or 0 0.04% below V of or 0 0.03% below V of or 0 0.02% below V of or 0 0.01% below V of Or Those The section Minute range or combination It may have.

[0044] Precipitation hardening of any of the embodiments described above type Stainless steel alloy is heavy standard in, 0 0.09% below Sn, or 0.08% below of Sn, or 0 .07% below of Sn, or 0 .06% below of Sn, or 0 .05% below of Sn, or 0 .04% below of Sn, or 0 .03% below of Sn, or 0 .02% below of Sn, or 0 .01% below of Sn, or 0 .005% below of Sn, or 0 .001% below of Sn, Or They The section may have a or combination range.

[0045] Any precipitation hardening type stainless steel alloy of the foregoing embodiments is by weight standard , 0 .025% below of P, or 0 .02% below of P, or 0 .015% below of P, or 0 .01% below of P, or 0 .005% below of P, or 0 .001% below of P, Or They The section may have a or combination range.

[0046] Any precipitation hardening type stainless steel alloy of the foregoing embodiments is by weight standard , 0 .007% below of S, or 0 .006% below of S, or 0 .005% below of S, or 0 .004% below of S, or 0 .003% below of S, or 0 .002% below of S, or 0 .001% below of S, Or they The section range or combination may have.

[0047] Precipitation hardening of any of the foregoing embodiments type stainless steel alloy is by weight standard and, 0 .09% below of As, or 0 .08% below of As, or 0 .07% below of As, or 0 .06% below of As, or 0 .05% below of As, or 0 .04% below of As, or 0 .03% below of As, or 0 .02% below of As, ... or 0 .01% below of As, or 0 .005% below of As, or 0 .001% below of As, Or they The section range or combination may have.

[0048] Precipitation hardening of any of the foregoing embodiments type stainless steel alloy is by weight ... standard and, 0 .009% [[ID=B2]] below of Sb, or 0 .008% below of Sb, or 0 .007% below of Sb, or 0 .006% below of Sb, or 0 .005% below of Sb, or 0 .004% below of Sb, or 0 .003% below of Sb, or 00.002% below Sb, or 0 0.0015% below Sb, or 0 0.001% below Sb, Or Those The section Minute range or combination It may have.

[0049] C, Mn, Si, V, Sn, N, P, S, As, disclosed herein and Any of the narrow ranges of Sb is any combination And other narrow ranges of these elements combination It is possible to obtain the range combination This refers to the precipitation hardening disclosed herein. type It is specifically disclosed that this can be applied to any embodiment of stainless steel alloys.

[0050] Without limiting the scope of this disclosure, one exemplary precipitation hardening process is described. type Stainless steel alloy is heavy standard So, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.045% C, or 0.030-0.045% C, 0.2-0.5% Mn, 0.2-0.5% Si, 0 0.05% below V of 0 0.1% below Co, 0 0.01% below Sn, 0 0.01% below N of 0 0.01% below P, 0 0.05% below Al of 0 0.005% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.1% below As, 0 0.01% below Sb, and The alloy contains the remaining Fe, and is 15:1 That's all. Nb:(C+N )ratio It has. Another exemplary precipitation hardening. type Stainless steel alloy is heavy standard So, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.045% C, or 0.030-0.045% C, 0.2-0.5% Mn, 0.2-0.5% Si, 0 0.05% below V of 0 0.1% below Co, 0 0.01% below Sn, 0 0.01% below N of 0 0.01% below P, 0 0.05% below Al of 0 0.005% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.1% below As, 0 0.01% below Sb, 0 0.5% below of other element Consists of Inevitable impurities, or 0 0.4% below of other element Consists of Inevitable impurities, or 0 0.3% below of other element Consists of Inevitable impurities, or 0 0.2% below of other element Consists of Inevitable impurities, or 0 0.1% below of other element Consists of Inevitable impurities, or 0 0.05% below of other element Consists of Inevitable impurities, or 0 0.01% below of other element Consists of Inevitable impurities, and The remainder is Fe, and the alloy is 15:1 That's all. Nb:(C+N )ratio It has. Another exemplary precipitation hardening. type Stainless steel alloy is heavy standard So, 14.0-16.0% Cr, 6.0-7.0% Ni, 1.25-1.75% Cu, 0.5-1.0% Mo, 0.40-0.85% Nb, 0.025-0.045% C, or 0.030-0.045% C, 0.2-0.5% Mn, 0.2-0.5% Si, 0 0.05% below V of 0 0.1% below Co, 0 0.01% below Sn, 0 0.01% below N of 0 0.01% below P, 0 0.05% below Al of 0 0.005% below S of 0 0.005% below Ag, 0 0.005% below Pb, 0 0.1% below As, 0 0.01% below Sb, and The remainder is Fe, and the alloy is 15:1 That's all. Nb:(C+N )ratio It holds.

[0051] In one embodiment, precipitation hardening occurs. type Stainless steel alloys are 0 0.045% below C of 0 0.5% below Mn, 0 0.5% below Si, 0 0.05% below V of 00.01% below Sn, 0 0.01% below N of 0 0.01% below P, 0 0.005% below S of 0 0.01% below As, and 0 0.002% below The alloy contains Sb, and is composed of over 0.045% C, over 0.5% Mn, over 0.5% Si, over 0.05% V, over 0.01% Sn, over 0.01% N, over 0.01% P, over 0.005% S, over 0.01% As, and over 0.002% Sb. or Those combination has Except for the dot identical contrast Compared to alloys, embrittlement is reduced.

[0052] In one embodiment, precipitation hardening occurs. type Stainless steel alloys are 0 0.045% below C of 0 0.5% below Mn, 0 0.5% below Si, 0 0.05% below V of 0 0.01% below Sn, 0 0.01% below N of 0 0.01% below P, 0 0.005% below S of 0 0.01% below As, and 0 0.002% below The alloy contains Sb, and is composed of over 0.045% C, over 0.5% Mn, over 0.5% Si, over 0.05% V, over 0.01% Sn, over 0.01% N, over 0.01% P, over 0.005% S, over 0.01% As, and over 0.002% Sb. or Those combination has Except for the dot identical contrast Compared to alloys, Fracture surface transition The temperature is low.

[0053] precipitation hardening type While stainless steel alloys have been described with reference to preferred embodiments, it will be understood by those skilled in the art that various modifications can be made and elements can be replaced with equivalents without departing from the scope of this disclosure. In addition, without departing from the essential scope of this disclosure, certain circumstances or Many modifications can be made to adapt the materials to the teachings of this disclosure. Therefore, this disclosure is not limited to any particular embodiment disclosed as the best mode intended for carrying out the art, and this disclosure is intended to include all embodiments that fall within the scope of the appended claims.

Claims

1. 1. A precipitation hardening stainless steel alloy comprising, by weight: 14.0 to 16.0% Cr, 6.0 to 7.0% Ni, 1.25 to 1.75% Cu, 0.5 to 1.0% Mo, 0.40 to 0.85% Nb, 0.025 to 0.05% C, 1.0% max Mn, max 1.0% Si, V up to 0.1% max. 0.1% Co, maximum 0.1% Sn, Maximum 0.02% N, maximum 0.025% P, max. 0.05% Al, Maximum 0.008% S, maximum 0.005% Ag, maximum 0.005% Pb, Maximum 0.1% As, 0.01% maximum Sb, and Remaining Fe Including, the alloy has a Nb:(C+N) ratio of at least 15:1; Precipitation hardening stainless steel alloy.

2. 10. The alloy of claim 1, containing, by weight, 0.03-0.05% C.

3. 10. The alloy of claim 1 containing, by weight, a maximum of 0.01% N.

4. By weight, 14.0 to 16.0% Cr, 6.0 to 7.0% Ni, 1.25 to 1.75% Cu, 0.5 to 1.0% Mo, 0.40 to 0.85% Nb, 0.025 to 0.05% C, maximum 1.0% Mn, max 1.0% Si, V up to 0.1% max. 0.1% Co, maximum 0.1% Sn, Maximum 0.02% N, maximum 0.025% P, max. 0.05% Al, Maximum 0.008% S, maximum 0.005% Ag, maximum 0.005% Pb, Maximum 0.1% As, maximum 0.01% Sb, unavoidable impurities of up to 0.5% of additional elements, and Remaining Fe It consists of the alloy has a ratio of Nb:(C+N) of at least 15:1; 10. The alloy of claim 1.

5. By weight, 14.0 to 16.0% Cr, 6.0 to 7.0% Ni, 1.25 to 1.75% Cu, 0.5 to 1.0% Mo, 0.40 to 0.85% Nb, 0.025 to 0.05% C, maximum 1.0% Mn, max 1.0% Si, V up to 0.1% max. 0.1% Co, maximum 0.1% Sn, Maximum 0.02% N, maximum 0.025% P, max. 0.05% Al, Maximum 0.008% S, maximum 0.005% Ag, maximum 0.005% Pb, Maximum 0.1% As, 0.01% maximum Sb, and Remaining Fe It consists of the alloy has a ratio of Nb:(C+N) of at least 15:1; The alloy of claim 4.

6. By weight, 0.025 to 0.045% C, 0.2 to 0.5% Mn, 0.2 to 0.5% Si, V up to 0.05% maximum 0.01% Sn, Maximum 0.01% N, maximum 0.01% P, Maximum 0.005% S, 0.01% maximum As, and Maximum 0.002% Sb 10. The alloy of claim 1, comprising:

7. By weight, 14.0 to 16.0% Cr, 6.0 to 7.0% Ni, 1.25 to 1.75% Cu, 0.5 to 1.0% Mo, 0.40 to 0.85% Nb, 0.025 to 0.045% C, 0.2 to 0.5% Mn, 0.2 to 0.5% Si, V up to 0.05% max. 0.1% Co, maximum 0.01% Sn, Maximum 0.01% N, maximum 0.01% P, max. 0.05% Al, Maximum 0.005% S, maximum 0.005% Ag, maximum 0.005% Pb, Maximum 0.01% As, maximum 0.002% Sb, unavoidable impurities of up to 0.5% of additional elements, and Remaining Fe It consists of the alloy has a ratio of Nb:(C+N) of at least 15:1; The alloy of claim 6.

8. By weight, 14.0 to 16.0% Cr, 6.0 to 7.0% Ni, 1.25 to 1.75% Cu, 0.5 to 1.0% Mo, 0.40 to 0.85% Nb, 0.025 to 0.045% C, 0.2 to 0.5% Mn, 0.2 to 0.5% Si, V up to 0.05% max. 0.1% Co, maximum 0.01% Sn, Maximum 0.01% N, maximum 0.01% P, max. 0.05% Al, Maximum 0.005% S, maximum 0.005% Ag, maximum 0.005% Pb, Maximum 0.01% As, 0.002% maximum Sb, and Remaining Fe It consists of the alloy has a ratio of Nb:(C+N) of at least 15:1; 8. The alloy of claim 7.

9. 7. The alloy of claim 6, wherein the alloy exhibits reduced embrittlement and a lower fracture appearance transition temperature compared to an otherwise identical comparative alloy having more than 0.045% C, more than 0.5% Mn, more than 0.5% Si, more than 0.05% V, more than 0.01% Sn, more than 0.01% N, more than 0.01% P, more than 0.005% S, more than 0.01% As, more than 0.002% Sb, or combinations thereof.

10. 10. The alloy of claim 1, wherein the alloy has reduced susceptibility to intergranular corrosion for reverse austenite adjacent grain boundaries and forms less reverse austenite during heat treatment compared to otherwise identical comparative alloys having a comparative ratio of Nb:(C+N) less than 15:

1.

11. 10. The alloy of claim 1, wherein the alloy has at least 25% less reverse austenite after heat treatment at 577°C for 500 minutes than an otherwise identical comparative alloy having a comparative ratio of Nb:(C+N) less than 15:1 after heat treatment at 577°C for 500 minutes.

12. 10. The alloy of claim 1, wherein the alloy contains less than 16% reverse austenite after heat treatment at 577°C for 500 minutes.

13. 10. The alloy of claim 1, wherein at least 90% of all C and N in the alloy is sequestered as Nb-C, Nb-N, and Nb-C-N species.

14. 2. The alloy of claim 1, wherein the ratio of Nb:(C+N) is from 15:1 to 34:

1.

15. 15. The alloy of claim 14, wherein the ratio of Nb:(C+N) is from 15:1 to 18:1.

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